Electronic circuits use signals to perform functions. Some circuits use a single signal for a function. Some other circuits use two signals as a complementary signal pair for other functions in which one of the two signals is an inverted version of the other signal.
An inverter is usually used to generate an inverted signal (inverted version) of an input signal. The inverter has a time delay. Thus, the inverted signal generated by the inverter has a delay relative to the original input signal. In some cases, the delay caused by the inverter is negligible for some function. Hence, in some cases, the inverted signal generated by the inverter and the original input signal are used together as the complementary signal pair. However, in cases where synchronization between the original input signal and the inverted signal is needed, the inverted signal and the original input signal are unsuitable.